Snap-on radial mounted printed die



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Nov. 20, 1956 R. w. KNAPP SNAP-ON RADIAL MOUNTED PRINTED DIE Filed Feb.25, 1953 United States Patent SNAP-ON RADIAL MOUNTED PRINTED DIE RudolphW. Knapp, Chicago, Ill., assignor to The Pannier Corporation,Pittsburgh, Pa., a corporation of Pennsylvania Application February 25,1953, Serial No. 338,803

3 Claims. (Cl. 101-415.1)

This invention relates generally to printing dies and more particularlyto rubber-printing dies fastened to a printing drum.

Printing dies may be formed of an elastomer such as rubber and areprovided with a flexible backing such as a thin strip of brass or othersuitable metal. The brass has a hole at each end to admit mountingscrews which secure the die to the surface of a drum. Since the rubberdie is completely backed with the brass strip, it cannot give or stretchlongitudinally and the holes in the metal strip must exactly mate withthe holes in the printing drum or the die cannot be properly mounted.

Frequently, the mounting holes in the metal backing strip of arubber-printing die vary, and it is necessary to thread holes atdiiferent lengths in the drum to accommodate these variations. Itrequires a considerable amount of time to hunt for the proper mountinghole and then one has to have a screw driver and turn or move screws tofasten the printing die to the printing drum. When frequent changes ofthe die are required, it may take considerable time to handle the screwdriver for removing and replacing these rubber dies.

The principal object of this invention is the provision of a newstructure and manner of mounting these dies on a printing drum to avoidall the difiiculties connected with a completely metal backed rubberdie. These improvements are obtained by providing a metal backing foronly that portion of the rubber die that carries the letters or symbolsbeing printed. This insures proper maintenance in the spacing of thecharacters. The ends of the die are formed of rubber and are permittedto be elastic so that they may stretch. By having a hole in theseelastic ends, one may readily snap off or snap on the die without theuse of tools such as a screw driver or screws. A set of spaced posts maybe set in the printing drum and by merely snapping the die on the posts,one may change the same in less than two or three seconds," where thechanging of dies by screws takes a matter of minutes.

Again the rubber dies need not be backed with metal but may have arubber base that is less resilient with the more resilient charactersthereon and the resilient ears at the ends of the strap to snap them onthe pins held by the printing drum.

The pins may have a small head something like that of a finishing nailto aid in holding the elastic ears of the rubber die in place. Thesepins may be slightly tapered so that they will become firmly locked inplace, or they may be a threaded bolt adjustably mounted in an annularslot. One pin may be in the form of a hook while the other remains aheaded pin.

The elastic ears at the ends of the strap forming this rubber printingdie may have metal grommets or eyelets formed within the rubber or putin after the rubber ears have been formed to increase the wear of a diethat is expected to have considerable use over anextended period oftime. This reinforcing saves the hole from wearing and maintains the diein proper position on the drum.

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A portion of the elastic ear at the ends of the rubber die extendsbeyond the mounting hole and is provided with a ribbed or roughenedsurface to aid the fingers in grasping and stretching the ears to snapthe holes over the mounting pins. This aids in mounting the die and thefact that these elastic ears must bestretched to snap their mountingholes on the pins providesa .tension on the strap-shaped rubber-printingdie, that keeps it tightly against the surface of the drum. This is notassured when the whole length ofthe strap is reinforced by a metal plateand the holes do not quite match the mounting holes in the drum and thedienwillvnot snugly fit the surface of the drum, which results in badprinting. This new structure avoids all these dfii-iculties.

Other objects and advantages appear hereinafter in the followingdescription and accompanying drawing.

The accompanying drawings show for the purpose of exemplificationwithout limiting the invention or claims thereto certain practicalembodiments, wherein:

Fig. l is a plan view of a rubber printing die comprising thisinvention.

Fig. 2 is a side elevation of the structure shown in Fig. 1.

Fig. '3 is a sectional view taken on the line 33 of Fig. 1.

Fig. 4 is a view showing a different manner of applying the eyelet shownin Fig. 3.

Fig. 5 is a view of reduced scale showing the application of theprinting die to a printing drum.

Fig. 6 is an enlarged detailed sectional view illustrating the fasteningof the rubber die ear on a mounting pin.

Referring to the drawings, the rubber printing die 1 is provided with abase section 2 backed up with a flexible metal strip 3 such as brass, towhich the base is vulcanized. The rubber base actually is vulcanizedover the perimetrical edge of the flexible plate 3 and thus practicallyembeds the same. The top of the base 2 has the characters 4 vulcanizedthereon. The numerals 5 may be removably inserted in pockets 6.

The ends of the rubber die strap are referred to as elastic ears 7 and 8and are flexible for their full extent as indicated in the drawing asbeing from the end of the plate 3 to the tip of the ears. Each ear has afinger tab 10, the top and bottom surfaces of which are ribbed asindicated in the drawing to prevent the finger from slipping and toreadily permit the ears to be lengthened. At approximately half of thelength of each ear, they are provided with a hole 11 that may bereinforced by the eyelet 12, which in Figs. 1 to 3 is embedded andvulcanized within the ear, but in Fig. 4 is merely set in the hole 11after the ears have been formed.

As shown in Fig. 5 the die 1 is shown being mounted on the printing drum13 that is mounted on the shaft 14. A fixed or anchor pin 15 is securedto the drum and a second pin 16 is adjustably set on the drum in spacedrelation with the pin 15. Each of these pins is provided with a smallhead 17 as shown in'Fig. 6. This head is upset a little and thusprevents the hole in the die ear from slipping off the pin.

It will be noted in Fig. 5 that the hole 11 in the ear 8 will not quitemake the pin 15, and it is therefore necessary to pull and stretch theears. When this is done, both ears stretch and the ear 8 is snapped overthe head of the pin 15 thus insuring that the back of the die lays tightand snug against the perimetral surface of the drum and remains properlycentered or positioned on the drum. This was not always true of thescrew mounted dies.

It is understood that the invention disclosed herein is not limited inits application to the details of construction and arrangement of partsillustrated in the accompanying drawing since the invent-ion is capableof other embodiments and of being practiced or carried out in variousways of having this elastic" sectionto hold the die tight against thedrum and make it quickly applied or removed therefrom.

I claim:

1. A fiexible printing die comprising'a flexible inelastic rubber base,a flexible stiffener member secured to said rubber base; printingcharacters on said rubber base above said flexible inelastic stiffenermember, an elastic earon at least one end-of saidflexible rubber basebeyond said stiffener member, die attaching'means carried by said ear,and a separate ribbed finger tab attached to said ear beyond said dieattaching means to stretch said ear forconnecting and disconnecting saiddie attaching means.

2. The structure of claim 1 characterizedin that said rubber base hastwo ofsaid elasticears, each ear posi-- tioned on said flexible rubberbase beyond said stiffening member, each ear having a dieattachingmeans, and a separate ribbed finger tab attached to each ear to stretchboth ears for connecting and disconnecting said' die attaching means ofboth ears.

3. The structure of claim 1 characterized in that said die attachingmeans is means defining a hole in said car.

References Cited in the file of this patent UNITED STATES PATENTS336,481 Hall Feb; 16, 1886 1,093,831 Cornwall Apr; 21, 1914 1,451,204Chisholm Apr; 10, 1923 1,464,068 Forrester Aug. 7, 1923 1,531,554 HarleyMar. 3 1, 1925 1,629,376 Buck May 17, 1927 1,681,999 Smith Aug. 28, 19281,695,575 Cohen Dec. 18, 1928 1,941,681 Gollwitzer Jan. 2, 19342,285,060 Schrnutz June 2, 1942

